So, it sounds like you've covered the simple bases. My first recommendation is to find a VERY competent sports doc/PT/chiro who works with athletes. If you had physio exercises that you had to quit (i.e., were doing more harm than good) and that weren't adjusted in response, I'm sceptical about the caregiver you were working with (if you were working with one). If it was you, I understand: I've done more harm than good to myself sometimes before (finally) moving forward.
I can only give the most general advice, b/c I haven't had personal experience with pain in that part of the clavicle (excepting when I broke mine ... then the whole damn thing hurt).
1. RICE. If you are really pained under the clavicle, icing may be difficult but try. Elevation is so easy with appendages. Not so easy with stuff in the abdomen and thorax.
2. Ibuprofen bomb if you are content with the cost-benefit tradeoff.
3. Look upstream and downstream as Guru Starrett has taught us. At the SC joint, this would involve lots of stuff: down towards the pecs, back towards the traps, out towards the shoulder (deltoid), up towards the neck. If you are looking to manage this yourself, try to get these systems to give slack around the point of pain. Note that your focus (to this point) has been on only a few of these.
4. Posture (sitting if you are desk jockey/driver and sleeping). In particular, head/neck/thoracic.
The tone of your post indicates that you are frustrated and in pain. You may well have enough going wrong that indirectly related systems are reacting to the trauma and shutting down also (e.g., the lats overhead excessive tightness).